Thursday 22 May 2008 19.01 EDT
First published on Thursday 22 May 2008 19.01 EDT

The UN secretary general, Ban Ki-moon, praised "the will, resilience and the courage of the people of Myanmar" yesterday, before embarking on a carefully managed four-hour helicopter tour of the Irrawaddy delta, where most of the estimated 134,000 cyclone victims died.

Ban changed from a business suit into a beige casual jacket, baseball cap and trousers before boarding the military helicopter, and flew over flooded rice fields, to witness the extensive damage to trees, homes and other structures.

He was then taken to a well-ordered relief camp with tents in neat rows - scenes that contrasted sharply with the UN and aid agencies' view that three-quarters of the 2.4 million affected had yet to receive any aid.

"I am so sorry, but don't lose your hope," Ban told one woman as he peered into a tent at the Kyondah relief camp 45 miles south of Rangoon.

"The United Nations is here to help you. The whole world is trying to help Myanmar."

State-run TV showed footage of the official tour, Ban shaking hands and talking to survivors.

In a 90-minute meeting beforehand in Rangoon, Burmese prime minister Lt Gen Thein Sein told Ban that the rescue and relief phase of the operation was ending and the reconstruction and rehabilitation could start.

But Burma has blocked significant amounts of aid and kept out large numbers of international disaster management specialists with the expertise to scale up relief, apparently fearful that their presence could loosen the regime's 46-year grip on power.

Surin Pitsuwan, secretary-general of the Association of South-east Asian Nations (Asean), warned that "the [Burmese] authorities insist that the rescue and relief phase is over, but competent international agencies say that assertion can't be verified". Surin, who is head of an Asean taskforce set up to funnel outside help to Burma, added: "We do not know the extent of the damage, we don't know the numbers of the dead, the numbers of the missing, or even the numbers of displaced."

Ban said he was "very upset" by what he had seen. Earlier he had promised: "I bring a message of hope for the people of Myanmar."

Later today, when Ban travels to the remote new capital of Naypidaw, 250 miles north-east of Rangoon, he will meet the junta's 11 ruling generals for what is probably a last-chance attempt to persuade them to accept desperately needed international aid and expert help from disaster specialists.

He will also meet Than Shwe - in whose hands power is concentrated - to warn him of the gravity of the situation ahead of a donor conference in Rangoon on Sunday, backed by ASEAN and the UN.

The ASEAN taskforce has set tests the regime must meet if it is to reach international standards and win donors' confidence to achieve the target of £5.5bn it deems necessary for reconstruction.

Among the conditions the taskforce says must be met is that more international relief workers be allowed into the stricken areas to ensure a higher degree of transparency. Foreign aid staff are currently barred from the Irrawaddy delta.

Aside from asking that international teams verify the true scale of the disaster, which is now three weeks old, Ban will also press Than Shwe to accept that Burma needs far broader assistance with what the regime acknowledges is an unprecedented tragedy.

With 60% of the delta's infrastructure destroyed by the cyclone - whose official tolls of dead and missing stand at 77,738 and 55,917 - Ban also wants the regime to allow more helicopters and ships into the delta to deliver vital food, shelter and medical supplies.